Service providers are migrating their Layer 0 (wavelength-division multiplexing management or WDM) and Layer 1 (time-division multiplexing or TDM) core networks into integrated intelligent optical transport networks (IOTNs). In some cases, previous network management system (NMS)-based procedures are being phased out by the deployment of an intelligent control plane in the IOTNs. IOTNs may support mesh topology to achieve better resource utilization and may support a distributed control plane to fully automate networking functions, such as network topology discovery, network resource discovery, end-to-end path calculation, end-to-end path provisioning and activation, and protection & restoration (P&R). The IOTN control plane and mesh topology together have provided opportunities for service providers to develop advanced optical transport network (OTN) services that are better tailored to the business needs of wholesale and enterprise customers.